diff --git a/pkg/core/interop/contract/call.go b/pkg/core/interop/contract/call.go
index 279bbb5e3..aa5989c6d 100644
--- a/pkg/core/interop/contract/call.go
+++ b/pkg/core/interop/contract/call.go
@@ -14,6 +14,7 @@ import (
 	"github.com/nspcc-dev/neo-go/pkg/smartcontract/callflag"
 	"github.com/nspcc-dev/neo-go/pkg/smartcontract/manifest"
 	"github.com/nspcc-dev/neo-go/pkg/util"
+	"github.com/nspcc-dev/neo-go/pkg/vm"
 	"github.com/nspcc-dev/neo-go/pkg/vm/stackitem"
 )
 
@@ -67,11 +68,11 @@ func Call(ic *interop.Context) error {
 		return fmt.Errorf("method not found: %s/%d", method, len(args))
 	}
 	hasReturn := md.ReturnType != smartcontract.VoidType
-	return callInternal(ic, cs, method, fs, hasReturn, args, !hasReturn)
+	return callInternal(ic, cs, method, fs, hasReturn, args, true)
 }
 
 func callInternal(ic *interop.Context, cs *state.Contract, name string, f callflag.CallFlag,
-	hasReturn bool, args []stackitem.Item, pushNullOnUnloading bool) error {
+	hasReturn bool, args []stackitem.Item, isDynamic bool) error {
 	md := cs.Manifest.ABI.GetMethod(name, len(args))
 	if md.Safe {
 		f &^= (callflag.WriteStates | callflag.AllowNotify)
@@ -83,12 +84,12 @@ func callInternal(ic *interop.Context, cs *state.Contract, name string, f callfl
 			}
 		}
 	}
-	return callExFromNative(ic, ic.VM.GetCurrentScriptHash(), cs, name, args, f, hasReturn, pushNullOnUnloading, false)
+	return callExFromNative(ic, ic.VM.GetCurrentScriptHash(), cs, name, args, f, hasReturn, isDynamic, false)
 }
 
 // callExFromNative calls a contract with flags using the provided calling hash.
 func callExFromNative(ic *interop.Context, caller util.Uint160, cs *state.Contract,
-	name string, args []stackitem.Item, f callflag.CallFlag, hasReturn bool, pushNullOnUnloading bool, callFromNative bool) error {
+	name string, args []stackitem.Item, f callflag.CallFlag, hasReturn bool, isDynamic bool, callFromNative bool) error {
 	for _, nc := range ic.Natives {
 		if nc.Metadata().Name == nativenames.Policy {
 			var pch = nc.(policyChecker)
@@ -123,7 +124,7 @@ func callExFromNative(ic *interop.Context, caller util.Uint160, cs *state.Contra
 	if wrapped {
 		ic.DAO = ic.DAO.GetPrivate()
 	}
-	onUnload := func(commit bool) error {
+	onUnload := func(ctx *vm.Context, commit bool) error {
 		if wrapped {
 			if commit {
 				_, err := ic.DAO.Persist()
@@ -135,8 +136,13 @@ func callExFromNative(ic *interop.Context, caller util.Uint160, cs *state.Contra
 			}
 			ic.DAO = baseDAO
 		}
-		if pushNullOnUnloading && commit {
-			ic.VM.Context().Estack().PushItem(stackitem.Null{}) // Must use current context stack.
+		if isDynamic && commit {
+			eLen := ctx.Estack().Len()
+			if eLen == 0 && ctx.NumOfReturnVals() == 0 { // No return value and none expected.
+				ic.VM.Context().Estack().PushItem(stackitem.Null{}) // Must use current context stack.
+			} else if eLen > 1 { // 1 or -1 (all) retrun values expected, but only one can be returned.
+				return errors.New("multiple return values in a cross-contract call")
+			} // All other rvcount/stack length mismatches are checked by the VM.
 		}
 		if callFromNative && !commit {
 			return fmt.Errorf("unhandled exception")
diff --git a/pkg/vm/context.go b/pkg/vm/context.go
index 31c4280f7..6c086249f 100644
--- a/pkg/vm/context.go
+++ b/pkg/vm/context.go
@@ -73,7 +73,7 @@ type Context struct {
 }
 
 // ContextUnloadCallback is a callback method used on context unloading from istack.
-type ContextUnloadCallback func(commit bool) error
+type ContextUnloadCallback func(ctx *Context, commit bool) error
 
 var errNoInstParam = errors.New("failed to read instruction parameter")
 
@@ -239,6 +239,11 @@ func (c *Context) GetNEF() *nef.File {
 	return c.sc.NEF
 }
 
+// NumOfReturnVals returns the number of return values expected from this context.
+func (c *Context) NumOfReturnVals() int {
+	return c.retCount
+}
+
 // Value implements the stackitem.Item interface.
 func (c *Context) Value() interface{} {
 	return c
diff --git a/pkg/vm/vm.go b/pkg/vm/vm.go
index 378a898b2..44e3f50d5 100644
--- a/pkg/vm/vm.go
+++ b/pkg/vm/vm.go
@@ -1634,7 +1634,7 @@ func (v *VM) unloadContext(ctx *Context) {
 			ctx.sc.static.ClearRefs(&v.refs)
 		}
 		if ctx.sc.onUnload != nil {
-			err := ctx.sc.onUnload(v.uncaughtException == nil)
+			err := ctx.sc.onUnload(ctx, v.uncaughtException == nil)
 			if err != nil {
 				errMessage := fmt.Sprintf("context unload callback failed: %s", err)
 				if v.uncaughtException != nil {